fun_present_check.cpp

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extern "C"
{
    typedef void (*funptr_t)();
}
 
// take the address of the function in a way
// that foils even clever optimizers
 
union {
    funptr_t      pf;
    unsigned long ul;
} funptri;
 
#ifdef CHECK_DECL
 
#  if defined (__linux__) && defined (__GNUG__) && __GNUG__ < 3
     // prevent empty exception specifications from triggering
     // gcc 2.9x -fhonor-std link errors looking for std::terminate()
#    include <features.h>
#    undef __THROW
#    define __THROW
#  endif   // gcc < 3 on Linux
 
#  include HDRNAME
 
#  ifndef NONAMESPACE
 
namespace std { }
using namespace std;
 
#  endif   // NONAMESPACE
 
int main (int argc, char**)
{
    // with gcc, prevent intrinsics from causing false positives
 
#  if TAKE_ADDR
 
    funptri.pf = (funptr_t)&FUNNAME;
 
    return (argc < 1 ? !funptri.ul : !!funptri.ul) + 0;
    
#  else   // if !TAKE_ADDR
 
    // disable warnings about an unused variable
    (void)&argc;
 
    // call the function using the supplied arguments
    #ifdef FUN_PARAMS
        FUN_PARAMS;
    #endif
    (void)FUN;
 
    return 0;
 
#  endif   // TAKE_ADDR
 
}
 
#else   // if !defined (CHECK_DECL)
 
extern "C" void FUNNAME ();
 
int main (int argc, char**)
{
    funptri.pf = (funptr_t)&FUNNAME;
 
    return (argc < 1 ? !funptri.ul : !!funptri.ul) + 0;
}
 
#endif   // CHECK_DECL